Polyamide-polyimide and polybenzoxazole-polyimide polymer

ABSTRACT

The present invention provides polyamide-polyimide and polybenzoxazole-polyimide polymers derived therefrom with improved processing and film characteristics having incorporated into the polymeric backbone the polymeric condensation residuum of novel aromatic diamino compounds having the formula: ##STR1## wherein A is selected from the group consisting of SO 2 , O, S, CO, C 1  to C 6  alkyl, perfluoroalkyl or perfluoroarylalkyl having from 1 to 10 carbon atoms and a carbon-carbon double bond directly linking the two aromatic groups, and R is hydrogen. 
     The polyamide-polyimide polymers of this invention are prepared by reacting compounds of the above formula, alone or admixed with other aromatic diamines, with one or more aromatic tetracarboxylic acids or anhydrides thereof. Polybenzoxazole-polyimide derivatives of such polyamide-polyimide.

This is a divisional of copending application Ser. No. 07/321,021 filedon 3-9-89 now U.S. Pat. No. 4,980,447.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to new fluorine-containing polyamide-polyimidepolymers and polybenzoxazole-polyimide polymers derived therefrom whichexhibit improved thermal stability, improved resistance to solvents,good processability, good film-forming properties and good filmcharacteristics.

2. Description of Related Art

Polyimides derived from aromatic diamine and dianhydride monomers arewidely used in the aerospace industry and electronics industry becauseof their toughness, low density, thermal stability, radiationresistance, mechanical strength and good dielectric properties. However,such polyimides are often difficult to process thermally and thin filmsprepared therefrom are often brittle and lack acceptable opticaltransparency.

It has been suggested that aromatic polyimides having thehexafluoroisopropylidene linking group in the diamine and/or dianhydridemonomer have improved solubility and processing properties. For example,U.S. Pat. No. 3,356,648 to Rogers discloses polyimides prepared from2,2-bis(4-aminophenyl) hexafluoropropane; U.S. Pat. No. 4,592,925 toDuPont discloses polyimides prepared from 2,2-bis(3-aminophenyl)hexafluoropropane; U.S. Pat. No. 4,111,906 to Jones et al. disclosespolyimides prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane; and U.S. Pat. No. 4,477,648 to Jones et al. disclosespolyimides prepared from 2,2-bis[(2-halo-4-amino-phenoxy)phenyl]hexafluoropropane. U.S. Pat. No. 4,592,925 discloses polyimides preparedby reacting 2,2-bis(3-aminophenyl) hexafluoropropane and4,4'-hexafluoroisopropylidene-bis (phthalic anhydride), also known as2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride.

In addition, U.S. Pat. No. 3,179,635 discloses the preparation ofpolyamide-polyimide polymers said to have good thermal stability andgood film-forming properties which may be prepared by condensing a tetrafunctional aromatic dianhydride, an aromatic diamine and an aromaticacid halide. U.K. patent application GB-2188936A discloses thepreparation of polyamides and polybenzoxazole derivatives thereof basedon the condensation product of2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane with an aromaticdicarboxylic acid or acid halide, followed by cyclization of thepolyamide to form a polybenzoxazole.

In applicant's co-pending application Ser. No. 076,098, filed in theUnited States Patent and Trademark Office on July 21, 1987, is disclosedhydroxy polyimide polymers which, in the preferred embodiment, areprepared by forming the polymeric condensation product ofhexafluoro-2,2-bis(3-amino-4-hydroxyphenyl) propane and2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride. Thesepolymers are particularly useful in the preparation of photoresistcompositions.

Whereas the above-referred to polyimides, polyamide-polyimide andpolybenzoxazole polymers are useful for the utilities disclosed, it isdesirable to provide polyamide-polyimide polymers and polybenzoxazolepolymers which provide not only superior thermal and thermooxidativestability, but also excellent thermal processibility, excellentresistance to solvents, low moisture uptake, low dielectric constant andgood film-forming properties and film characteristics.

SUMMARY OF THE INVENTION

The present invention provides polyamide-polyimide andpolybenzoxazole-polyimide polymers derived therefrom with improvedprocessing and film characteristics having incorporated into thepolymeric backbone the polymeric condensation residuum of novel aromaticdiamino compounds having the formula: ##STR2## wherein A is selectedfrom the group consisting of SO₂, O, S, CO, C₁ to C₆ alkyl,perfluoroalkyl or perfluoroarylalkyl having from 1 to 10 carbon atomsand a carbon-carbon double bond directly linking the two aromaticgroups, and R is selected from the group consisting of hydrogen, hydroxyand C₁ to C₄ alkoxy.

The polyamide-polyimide polymers of this invention are prepared byreacting compounds of Formula I, alone or admixed with other aromaticdiamines, with one or more aromatic tetracarboxylic acids or anhydridesthereof. Polybenzoxazole-polyimide derivatives of suchpolyamide-polyimide polymers are prepared utilizing compounds of FormulaI wherein R is hydroxy or C₁ to C₄ alkoxy, and by subjecting theresulting alkoxy or hydroxy-substituted polyamide-polyimide to adehydrating and cyclizing reaction to form the oxazole linkage whichgives rise to polybenzoxazole-polyimide polymer.

DETAILED DESCRIPTION OF THE INVENTION

In the more preferred embodiment of the present invention, the Rsubstituent and the amide linkage in Formula I are interchangeably inthe meta or para positions with respect to the A group, and the aminosubstituent groups are meta or para with respect to the amide linkage.

In the most preferred embodiment of the invention, A is ahexafluoroisopropylidene group ##STR3## or a1-phenyl-2,2,2-trifluroethane group ##STR4## and R is hydroxy. Compoundshaving the structure of Formula I are disclosed in Applicant's copendingapplication D-1278 filed in the United States Patent and TrademarkOffice on even date herewith, the disclosure of which application isincorporated herein by reference.

One embodiment of the polyamide-polyimide polymers of this invention maybe characterized as a polymer comprising recurring group of thestructure: ##STR5## wherein the moiety B is a substituted orunsubstituted tetravalent aromatic radical selected from the groupconsisting of a benzene nucleus, polyphenyl nuclei having up to fourphenyl rings, and naphthalene nuclei, n is an integer sufficient to giverise to a polymer having an inherent viscosity of at least 0.1 dl/g asmeasured from a solution of the polymer in dimethylacetamide at 25degrees Celsius at a polymer concentration of 0.5 weight percent, and Aand R are as set forth above in Formula I. In the moiety B, each pair ofcarbonyl groups are attached to adjacent carbon atoms in a ring of themoiety B.

Another preferred embodiment of this invention relates topolybenzoxazole polyimide polymers comprising at least one recurringgroup of the structure: ##STR6## wherein A, B and n are as definedabove. These polybenzoxazole polymers are derived frompolyamide-polyimide polymers of Formula II, wherein R is hydroxy or C₁to C₄ alkoxy positioned interchangeably at the meta or para positionswith respect to the A moiety, which are prepared by cyclization of theamide linkage to form the oxazole linkage.

Also within the scope of polymers of Formulas II and III arecopolyamide-polyimides and polybenzoxazoles derived therefrom wherein amixture of the diamine of Formula I and at least one different diamineare copolymerized, such a represented by the formula: ##STR7## wherein(II) represents a single condensed unit of Formula II, D represents theresiduum of a different aromatic diamine which may or may not contain anR substituent as defined above on the aryl nucleus, B and n are asdefined above, and (a) and (b) equal the mole fraction of each recurringunit in the polymer chain. Preferred polymers and copolymers of thestructure IV are those where the mole fractions of (a) and (b) are:

    a=0.01 to 1.0

    b=0.0 to 0.99;

more preferably:

    a=0.5 to 1.0

    b=0.0 to 0.5;

and most preferably:

    a=0.7 to 1.0

    b=0.0 to 0.3

Polyamide-copolyimides and polybenzoxazoles derived therefrom within thescope of Formulas II and III may also be prepared where the diamine ofFormula I is copolymerized with two or more different aromaticdianhydrides such as represented by the formula: ##STR8## wherein B'represents a tetravalent aromatic dianhydride of the B category butdifferent from the B component present in (II), and (II), A, R, a, b andn are as defined above.

Polybenzoxazoles having a structure analogous to the structures ofFormulas IV and V, wherein R is hydroxy or C₁ to C₄ alkoxy positionedinterchangeably at the meta and para positions with respect to the Amoiety, may be prepared by cyclizing the amide linkage to form theoxazole linkage as set forth above.

Preferred dianhydrides suitable for use in the present invention arebenzene and naphthalene tetracarboxylic acid dianhydrides and diphenyldianhydrides having the nuclear structure: ##STR9## wherein A is asdefined above in Formula I. Most preferred dianhydrides are those whereA is a hexafluoroisopropylidene group or a1-phenyl-2,2,2-trifluoroethane group.

Illustrative of tetracarboxylic acid dianhydrides which are suitable foruse in the present invention are:

1,2,4,5-benzene tetracarboxylic acid dianhydride;

1,2,3,4-benzene tetracarboxylic acid dianhydride;

1,4-bis(2,3-dicarboxyphenoxy) benzene dianhydride;

1,3-bis(3,4-dicarboxyphenoxy) benzene dianhydride;

1,2,4,5-naphthalene tetracarboxylic acid dianhydride;

1,2,5,6-naphthalene tetracarboxylic acid dianhydride;

1,4,5,8-naphthalene tetracarboxylic acid dianhydride;

2,3,6,7-naphthalene tetracarboxylic acid dianhydride;

2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride;

2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride;

2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride;

3,3',4,4'-diphenyl tetracarboxylic acid dianhydride;

2,2',3,3'-diphenyl tetracarboxylic acid dianhydride;

4,4'-bis(3,4-dicarboxyphenoxy)diphenyl dianhydride;

bis(2,3-dicarboxyphenyl) ether dianhydride;

4,4'-bis(2,3-dicarboxyphenoxy) diphenyl ether dianhydride;

4,4'-bis(3,4-dicarboxyphenoxy) diphenyl ether dianhydride;

bis(3,4-dicarboxyphenyl) sulfide dianhydride;

4,4'-bis(2,3-dicarboxyphenoxy) diphenyl sulfide dianhydride;

4,4'-bis(3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride;

bis(3,4-dicarboxyphenyl) sulfone dianhydride;

4,4'-bis(2,3-dicarboxyphenoxy) diphenyl sulfone dianhydride;

4,4'-bis(3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride;

3,3',4,4'-benzophenone tetracarboxylic acid dianhydride;

2,2',3,3'-benzophenone tetracarboxylic acid dianhydride;

2,3,3'4'-benzophenone tetracarboxylic acid dianhydride;

4,4'-bis(3,4-dicarboxyphenoxy) benzophenone dianhydride;

bis(2,3-dicarboxyphenyl) methane dianhydride;

bis(3,4-dicarboxyphenyl) methane dianhydride;

1,1-bis(2,3-dicarboxyphenyl) ethane dianhydride;

1,1-bis(3,4-dicarboxyphenyl) ethane dianhydride;

1,2-bis(3,4-dicarboxyphenyl) ethane dianhydride;

2,2-bis(2,3-dicarboxyphenyl) propane dianhydride;

2,2-bis(3,4-dicarboxyphenyl) propane dianhydride;

2,2-bis[4-(2,3-dicarboxyphenoxy) phenyl] propane dianhydride;

2,2-bis[4-(3,4-dicarboxyphenoxy) phenyl] propane dianhydride;

4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy) diphenyl-2,2-propanedianhydride;

2,2-bis[4-(3,4-dicarboxyphenoxy-3,5-dimethyl) phenyl] propanedianhydride;

2,3,4,5-thiophene tetracarboxylic acid dianhydride;

2,3,4,5-pyrrolidine tetracarboxylic acid dianhydride;

2,3,5,6-pyrazine tetracarboxylic acid dianhydride;

1,8,9,10-phenanthrene tetracarboxylic acid dianhydride;

3,4,9,10-perylene tetracarboxylic acid dianhydride;

2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride;

1,3-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride;

1,1-bis(3,4-dicarboxyphenyl)-1-phenyl-2,2,2-trifluoroethane dianhydride;

2,2-bis[4-(3,4-dicarboxyphenoxy) phenyl] hexafluoropropane dianhydride;

1,1-bis[4-(3,4-dicarboxyphenoxy) phenyl]-1-phenyl-2,2,2-trifluoroethanedianhydride;

4,4'-bis[2-(3,4-dicarboxyphenyl)hexafluoroisopropyl] diphenyl etherdianhydride,

and mixtures thereof.

One skilled in the art will recognize that the tetracarboxylic acids andacid-esters of the above-listed dianhydride compounds may also be usedto produce the polyimides. These tetracarboxylic acids or derivativesthereof are available or may be prepared by known methods. For example,U.S. Pat. No. 3,847,867 to Heath et al. and U.S. Pat. No. 4,650,850 toHowson, which are incorporated herein by reference, show the preparationof bis(ether anhydrides) and bis(dialkyl aromatic ether anhydrides),respectively. The preparation of fluorine-containing dianhydrides isdisclosed in U.S. Pat. No. 3,310,573 to Gordon and U.S. Pat. No.3,649,601 to Critchley et al., which are also incorporated herein byreference.

Copolyamide-polyimide copolymers may also be prepared using a mixture ofthe diamine of Formula I above and at least one other aromatic diaminehaving the formula:

    NH.sub.2 --D--NH.sub.2

wherein D is an aromatic moiety of a phenylene, naphthalene orbis-phenylene type compound which may be unsubstituted or ringsubstituted with halogen, hydroxy, C₁ to C₆ alkyl or C₁ -C₄ alkoxygroups.

Illustrative of diamines which are suitable for use in acopolymerization admixture with the diamine of Formula I include:

m-phenylene diamine;

p-phenylene diamine;

1,3-bis(4-aminophenyl) propane;

2,2-bis(4-aminophenyl) propane;

4,4'-diamino-diphenyl methane;

1,2-bis(4-aminophenyl) ethane;

1,1-bis(4-aminophenyl) ethane;

2,2'-diamino-diethyl sulfide;

bis(4-aminophenyl) sulfide;

2,4'-diamino-diphenyl sulfide;

bis(3-aminophenyl)sulfone;

bis(4-aminophenyl) sulfone;

4,4'-diamino-dibenzyl sulfoxide;

bis(4-aminophenyl) ether;

bis(3-aminophenyl) ether;

bis(4-aminophenyl)diethyl silane;

bis(4-aminophenyl) diphenyl silane;

bis(4-aminophenyl) ethyl phosphine oxide;

bis(4-aminophenyl) phenyl phosphine oxide;

bis(4-aminophenyl)-N-phenylamine;

bis(4-aminophenyl)-N-methylamine;

1,2-diamino-naphthalene;

1,4-diamino-naphthalene;

1,5-diamino-naphthalene;

1,6-diamino-naphthalene;

1,7-diamino-naphthalene;

1,8-diamino-naphthalene;

2,3-diamino-naphthalene;

2,6-diamino-naphthalene;

1,4-diamino-2-methyl-naphthalene;

1,5-diamino-2-methyl-naphthalene;

1,3-diamino-2-phenyl-naphthalene;

4,4'-diamino-biphenyl;

3,3'-diamino-biphenyl;

3,3'-dichloro-4,4'-diamino-biphenyl;

3,3'-dimethyl-4,4'-diamino-biphenyl;

3,4'-dimethyl-4,4'-diamino-biphenyl;

3,3'-dimethoxy-4,4'-diamino-biphenyl;

4,4'-bis(4-aminophenoxy)-biphenyl;

2,4-diamino-toluene;

2,5-diamino-toluene;

2,6-diamino-toluene;

3,5-diamino-toluene;

1,3-diamino-2,5-dichloro-benzene;

1,4-diamino-2,5-dichloro-benzene;

1-methoxy-2,4-diamino-benzene;

1,4-diamino-2-methoxy-5-methyl-benzene;

1,4-diamino-2,3,5,6-tetramethyl-benzene;

1,4-bis(2-methyl-4-amino-pentyl)-benzene;

1,4-bis(1,1-dimethyl-5-amino-pentyl)-benzene;

1,4-bis(4-aminophenoxy)-benzene;

o-xylylene diamine;

m-xylylene diamine;

p-xylylene diamine;

3,3'-diamino-benzophenone;

4,4'-diamino-benzophenone;

2,6-diamino-pyridine;

3,5-diamino-pyridine;

1,3-diamino-adamantane;

bis[2-(3-aminophenyl)hexafluoroisopropyl] diphenyl ether;

3,3'-diamino-1,1,1'-diadamantane;

N-(3-aminophenyl)-4-aminobenzamide;

4-aminophenyl-3-aminobenzoate;

2,2-bis(4-aminophenyl) hexafluoropropane;

2,2-bis(3-aminophenyl) hexafluoropropane;

2-(3-aminophenyl)-2-(4-aminophenyl)hexafluoropropane;

2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane;

2,2-bis[4-(2-chloro-4-aminophenoxy)phenyl] hexafluoropropane;

1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane;

1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane;

1,4-bis(3-aminophenyl)buta-1-ene-3-yne;

1,3-bis(3-aminophenyl) hexafluoropropane;

1,5-bis(3-aminophenyl) decafluoropentane;

4,4'-bis[2-(4-aminophenoxyphenyl) hexafluoroisopropyl] diphenyl ether;

and mixtures thereof;

Copolyamide-copolyimide polymers and polybenzoxazole polymers derivedtherefrom may also be prepared in accordance with this invention whereinboth a mixture of the above diamines and a mixture of the abovedianhydrides are reacted.

The polyamide-polyimides of this invention may be prepared by knownpolymerization techniques, typically by a high-temperature solutioncondensation method employing a condensation catalyst such asparatoluene sulfonic acid. Suitable solvents include N-methylpyrrolidone, gamma-butyrolactone, monochlorobenzene and mixturesthereof. The reaction is preferably conducted under substantiallyanhydrous conditions and for a time and at a temperature sufficient toprovide at least 50%, preferably at least 90%, of the correspondingpolyamic acid-polyamide, and then converting the polyamic acid-polyamideto the polyamide-polyimide. Such conversions may be accomplished byadding a suitable dehydration agent such a polyphosphoric acid, aceticanhydride or a mixture thereof with beta-picoline to the polyamic acidreaction media and stirring said mixture at room temperature untilimidization is substantially complete. Imidization may also beaccomplished by heating the polyamic acid solution or by forming a castfilm of the polyamic acid and stepwise heating the film from about 70degrees Celsius to about 250 degrees Celsius over a period of about 4hours.

The polyamide-polyimide polymers containing hydroxy or C₁ -C₄ alkoxysubstituents on aromatic carbons adjacent to the amido substituent maybe readily converted into the corresponding polybenzoxazole-polyimidepolymers of this invention by a further dehydrating and cyclizationreaction. This reaction is well known and is preferably accomplished byheating the polyamide-polyimide polymer for a sufficient period of timeand temperature to cyclize the amido/hydroxy or amido/alkoxy substituentgroups to form the oxazole linkage. The preferred method for cyclizationis to heat the polyamide-polyimide to a temperature of at least about300° C. for a period of at least about 1 hour. In general, the polyamicacid precursors and the polyamide-polyimide polymers of this inventionare soluble in common organic solvents, whereas the derivativepolybenzoxazole polymers are not. Thus, where shaped articles such asfilms or composites are prepared, it is preferred to first cast or moldthe desired shape, and then heat the casted or molded shape to form thesolvent insoluble polybenzoxazole.

The most preferred polyimides of this invention are prepared by formingthe polymeric condensation product of the diamine of Formula I abovewith 1,2,4,5-benzene tetracarboxylic acid dianhydride (also known aspyromelittic dianhydride-PMDA), bis(3,4-dicarboxy-phenyl) etherdianhydride (also known as oxyphthalic dianhydride-ODPA),3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (also known asbenzophenonetetracarboxylic dianhydride-BTDA), 3,4',4,4'-diphenyltetracarboxylic acid dianhydride (BPDA), 2,2-bis(3,4 dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), and 4,4'-bis[2-(3,4dicarboxyphenyl) hexafluoroisopropyl] diphenyl ether dianhydride (12FDA).

In the preferred embodiment of the present invention, the diamine anddianhydride monomers are reacted in approximately equi-molar amounts.

The following examples are illustrative in the invention.

EXAMPLE 1Bis-N,N'-(para-nitrobenzoyl)-hexafluoro-2,2-bis(4-hydroxyphenyl)propanehaving the following structure is prepared: ##STR10##

A 500 ml. round bottom flask equipped with a cooling jacket andmechanical stirrer was charged with 30.0 grams (0.082 mole) of2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and 400 mls. ofacetone. The mixture was stirred until the aminophenyl had dissolved,after which 39.6 grams (0.213 mole) of para-nitrobenzoyl chloridedissolved in 100 mls. of acetone was added dropwise over a period of 30minutes. The mixture was maintained at less than 20° C. during theaddition, after which the mixture was heated with agitation at 35°-40°C. for a period of two hours. 30.0 grams (0.218 mole) of potassiumcarbonate was then added gradually and the mixture was agitated for twoadditional hours at 35°-40° C. The heat was removed and the mixture wasagitated for an additional 18 hours at room temperature. Thereafter, 20mls. of water and 16 mls. of a 50% solution of sodium hydroxide wasadded with vigorous agitation and the mixture was heated at 50°-55° C.for 30 minutes. The heat was then removed and the mixture wastransferred to a beaker and the pH was adjusted in the range of 6.0 to7.0 by addition of HCL (37%) and 500 ml of additional water, addedincrementally over a period of 30 minutes under agitation. The mixturewas then filtered on an 11 cm. Buchner filter, and the precipitate waswashed with water and dried in an oven at 60°-70° C. The yield ofbis-N,N'-(para-nitrobenzoyl)-hexafluoro-2,2-bis(4-hydroxyphenyl) propanewas 93.6% of theoretical.

EXAMPLE 2

The product of Example 1 was purified by recrystallization in accordancewith the following method.

A 1000 ml. round bottom flask equipped with a mechanical stirrer wascharged with 51.0 grams of the crude product of Example 1, 316 grams ofacetone and 158 grams of methanol.

The mixture was stirred and heated at 40°-50° C. until the product ofExample 1 had dissolved. The mixture was cooled to room temperature and30 grams of Norite was gradually added after which the mixture wasstirred for about 25 minutes. The mixture was then clarified by passingit through a 9 cm. Buchner funnel and using a small amount of a 2 to 1mixture of acetone/methanol as a rinse. The clarified solution was thentransferred to a beaker and heated to 50°-55° C. 300 mls. of warm tapwater was added dropwise to the solution over a period of 30 minutes,after which the solution was heated to 60°-65° C. After removal from theheat, the solution was allowed to cool slowly to 20°-25° C. which causeda precipitate of the purified compound to be formed. The mixture wasfiltered using a 9 cm. Buchner funnel, washed with tap water, and ovendried at 60°-70° C. The yield of product was 44 grams which representsan 86.2% recovery.

EXAMPLE 3

This example illustrates the preparation ofbis-N,N'-(para-aminobenzoyl)-hexafluoro-2,2-bis(4-hydroxyphenyl) propaneby a reduction of the purified product of Example 2. The productprepared according to this Example has the structure: ##STR11##

A one liter Parr bottle was charged with 20.0 grams (0.03 mole) of thepurified product of Example 2, 1.0 grams of a 5% palladium on carboncatalyst and 180.4 grams of ethyl acetate to form a slurry. The slurrywas purged by bubbling nitrogen gas through it for 15 minutes. Thebottle was then connected to a shaker apparatus capable of maintainingintimate contact between gas, liquid and solid phases, following whichthe slurry was purged three times with hydrogen gas to insure a pressuretight seal. The shaker was started and the contents were subjected to 50psi hydrogen gas while heating at 50°-55° C. The mixture was shaken forabout 35 minutes. The mixture was then cooled to 35° C. After purgingthe resulting slurry with nitrogen, it was filtered to remove thecatalyst, after which the solvent was evaporated. The product was heatedin an air oven at 90° C. until dry, yielding 17.0 grams of driedproduct.

Other dinitro and diamino compounds within the scope of the presentinvention may be prepared by the processes described above or variationsthereof which will be evident to those skilled in the art.

The following examples illustrate the preparation of polyamide-polyimidepolymers and the polybenzoxazole derivatives thereof.

EXAMPLE 4

In a three neck 100 ml flask equipped with a thermometer, condenser,dean stark trap mechanical stirrer and nitrogen inlet tube, 3.02 grams(0.005 moles) of the diamine produced in Example 3 and 2.22 grams (0.005moles) of 2,2-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydridewere added to the flask along with 32 ml. of monochlorobenzene and 8 ml.of N-methyl pyrrolidone (NMP). The contents of the flask were heated to90° C. under agitation after which 0.06 grams of para-toluene sulfonicacid was added. The mixture was heated to reflux temperature at 142° C.after which an additional 16 ml of monochlorobenzene and 4 ml of NMPwere added. The contents of the flask were refluxed at 142°-145° C. for10 hours. 20 ml of NMP was then added and the monochlorobenzene wasdistilled off at 155° C. The reaction mixture was then cooled to roomtemperature and precipitated using an ice/water/methanol mixture. Theprecipitate was washed with water and oven dried overnight at 125° C.

The resulting polymer has an inherent viscosity of 0.60 dl/g indimethylacetamide as a 0.5% by weight solution at 25° C. and a numberaverage molecular weight of 37,000.

This polymer has the following structure: ##STR12##

The polymer was dissolved in NMP to form a solution which was cast on aglass plate. The coated plate was subjected to an oven heating cycle tocyclize the polyamic acid portion of the linkage to form apolyamide-imide polymer, e.g., 70° C./1 hour, 100° C./1 hour, 150° C./1hour, and 250° C./1 hour. A uniform flexible polymer film was obtainedhaving a glass transition temperature of 345° C., and which remainedsoluble in NMP. The film was then further heated for 2 hours at 350° C.to obtain a polybenzoxazole-polyimide film having a glass transitiontemperature of 367° C., which was insoluble in NMP.

EXAMPLE 5

The process of Example 4 was repeated except thatbis(3,4-dicarboxyphenyl)etherdianhydride (ODPA) was employed as thedianhydride monomer instead of 6F-DA. The monomers were present in thereaction media at a level of 3.02 gm (0.005 moles) of AHHP and 1.55 gm(0.005 moles) of ODPA.

EXAMPLE 6

The process of Example 4 was repeated, except that3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) wasemployed as the dianhydride monomer instead of 6F-DA. The monomers werepresent in the reaction media at a level of 3.02 gm (0.005 moles) ofAHHP and 1.62 gms (0.005 moles) of BTDA.

EXAMPLE 7

The process of Example 4 was repeated, except that 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) was employed as the dianhydridemonomer instead of 6F-DA. The monomers were present in the reactionmedia at a level of 3.02 gm (0.005 moles) of AHHP and 1.09 gm (0.005moles) of PMDA.

EXAMPLE 8

The process of Example 4 was repeated, except that 3,4',4,4'-diphenyltetracarboxylic acid dianhydride (BPDA) was employed as the dianhydridemonomer instead of 6F-DA. The monomers were present in the reactionmedia at a level of 3.02 gm (0.005 moles) of AHHP and 1.47 gm (0.005moles) of BPDA.

EXAMPLE 9

The process of Example 4 was repeated except that4,4'-bis[2-(3,4-dicarboxyphenyl) hexafluoroisopropyl]diphenyl etherdianhydride (12F-DA) was employed as the dianhydride monomer instead of6F-DA. The monomers were present in the reaction media at a level of3.02 gms (0.005 moles) of AHHP and 4.73 gm (0.005 moles of 12F-DA.

The inherent viscosity of each of the polyamide-polyimide polymersproduced in Examples 4-9 is reported in Table 1. Also reported are theweight average (Mw) and number average (Mn) molecular weights asmeasured by GPC, the glass transition temperatures of both thepolyamide-polyimide and polybenzoxazole-polyimide polymers as measuredby differential scanning calorimetry (DSC), and the characteristics offilms prepared from the polyamide-polyimide andpolybenzoxazole-polyimide films. The specific techniques for determiningmolecular weights and glass transition temperatures are standard methodsas disclosed in copending application D-1276, the disclosure of which isincorporated herein by reference. The term soluble as used in the Tablemeans solubility in N-methyl pyrrolidone (NMP) (as well as many othercommon solvents) while the term insoluble means insolubility in NMP.

As is evident from the data in Table 1, the polyamide-polyimide (PA-PI)and polybenzoxazole-polyimide (PBO-PI) polymers exhibit high glasstransition temperatures and the PA-PI polymers give rise to solventsoluble and flexible films. After conversion to the polybenzoxazoleform, the PBO-PI films are rendered solvent insoluble but retain theirgood flexibility except for the polymers of Examples 7 and 9.

                                      TABLE 1                                     __________________________________________________________________________                                 INHERENT                                                                             PA-PI                                     EXAMPLE                      VISC   GPC    PA-PI Film                                                                              PBO-PI Film              #      COMPONENT "A"                                                                            COMPONENT "B"                                                                            dl/g   Mw     Tg (°C.)                                                                    Film Tg                                                                                 Filmgree.C.)        __________________________________________________________________________    4      Diamine of Ex. 3                                                                         6F-DA      0.60   Mw = 76,000                                                                          345  Soluble                                                                            367  Insoluble                                               Mn = 37,000 Flexible  Flexible            5      Same       ODPA       0.57   Mw = 40,000                                                                          312  Soluble                                                                            375  Insoluble                                               Mn = 20,000 Flexible  Flexible            6      Same       BTDA       0.79   Mw = 80,000                                                                          336  Soluble                                                                            371  Insoluble                                               Mn = 18,000 Flexible  Flexible            7      Same       PMDA       0.21   *      *    Soluble                                                                            400  Insoluble                                                           Brittle   Brittle             8      Same       BPDA       0.55   *      *    Soluble                                                                            *    Insoluble                                                           Brittle   Flexible            9      Same       12-F DA    0.27   *      247  Soluble                                                                            *    Insoluble                                                           Flexible  Brittle             __________________________________________________________________________     *not tested                                                              

The polymers of this invention also exhibit improved thermal flowproperties and may be melt spun to form fibers and filaments. Because ofthe good solubility of the PA-PI polymers in common organic solvents,films may be cast from solvent solutions and optionally may be convertedto the polybenzoxazole form. Such films may be used as printed circuitbackings, insulating dielectric interlayers and other applications wheretough, flexible, high temperature stable films having good dielectricproperties have been used in the past.

The polymers of this invention may be molded using standard techniquessuch as compression molding or injection molding to produce meltfabricated articles such as safety masks, windshields, electroniccircuit substrates, airplane windows or the like. They may be compoundedwith graphite, graphite fiber, molybdenum disulphide or PTFE for theproduction of self-lubricating wear surfaces useful for piston rings,valve seats, bearings and seals. They may also be compounded with fiberssuch as glass, graphite or boron fibers to produce molding compounds forhigh strength structural components such as jet engine components. Thepolymers may also be compounded with friction materials to producemolding compounds for high temperature braking components or withabrasive materials such as diamonds for high speed grinding wheels.

The PA-PI polymers may be cast as films useful as wire and cable wraps,motor slot liners or flexible printed circuit substrates. They may beused as coatings on substrates such as aluminum or silicone dioxide.They are also useful to produce high temperature coatings for magneticwire, dip coatings for various electronic components, protectivecoatings over glass, metal and plastic substrates, wire coatings, andphotoresist coatings useful in microelectronic processing.

The PA-PI polymers may also be used to produce high temperatureadhesives for bonding aerospace structures or electrical circuitry,conductive adhesives when mixed with conductive fillers such as silveror gold for microelectronic applications, or adhesives for glass, metalor plastic substrates.

The polymers may also be used as varnish compositions or matrix resinsto produce composites and laminates. The varnish compositions and matrixresins may be used to impregnate glass or quartz cloth, or graphite orboron fibers, for the production of radomes, printed circuit boards,radioactive waste containers, turbine blades, aerospace structuralcomponents or other structural components requiring high temperatureperformance, non-flammability and excellent electrical properties.

It is to be understood that the above-described embodiments of theinvention are illustrative only and that modifications throughout mayoccur to those skilled in the art. Accordingly, this invention is not tobe regarded as limited to the embodiments disclosed herein, but is to belimited as defined by the appended claims.

What I claim is:
 1. A polyamide-polyimide polymer comprising at leastone recurring group of the structure: ##STR13## wherein the moiety B isa substituted or unsubstituted tetravalent aromatic radical selectedfrom the group consisting of a benzene nucleus, polyphenyl nuclei havingup to four phenyl rings and naphthalene nuclei, n is an integersufficient to give rise to a polymer having an inherent viscosity of atleast 0.1 dl/g as measured from a solution of the polymer indimethylacetamide at 25° C. at a polymer concentration of 0.5 weightpercent, A is selected from the group consisting of SO₂, O, S, CO, C₁ toC₆ alkyl, perfluoroalkyl or perfluoroarylalkyl having from 1 to 10carbon atoms, and a carbon-carbon double bond directly linking the twoaromatic groups, and R is hydrogen.
 2. The polymer of claim 1 whereinthe radical A is ##STR14##
 3. The polymer of claim 2 wherein the radicalA is ##STR15##
 4. The polymer of claim 3 wherein the amido linkages aremeta with respect to the A group.
 5. The polymer of claim 4 wherein theimido linkages are para with respect to each amido linkage.
 6. Thepolymer of claim 1 wherein the radical B is ##STR16##
 7. The polymer ofclaim 1 wherein B is the residuum nucleus of a dianhydride selected fromthe group consisting of 1,2,4,5-benzene tetracarboxylic aciddianhydride, bis(3,4-dicarboxy-phenyl) ether dianhydride,3,3',4,4'-benzophenone tetracarboxylic acid dianhydride,3,4',4,4'-diphenyl tetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and4,4'-bis[2-(3,4-dicarboxyphenyl) hexafluoroisopropyl] diphenyl etherdianhydride.
 8. The polymer of claim 7 wherein, A is ##STR17## and theamido linkages are meta with respect to the A group.
 9. The polymer ofclaim 8 wherein the imido linkages are para with respect to each amidolinkage.
 10. A solvent solution of the polymer of claim
 1. 11. A driedfilm comprising the polymer of claim 1.